Presently, cold joint terminals used for butting optical fibers are utilized with two different methods to fix the optical fibers.
In one method, the optical fibers are butted by compressing a folded sheet metal to fix the terminals of two optical fibers. Wherein, the folded sheet metal is arranged with a V-groove for butting the optical fibers; liquid substances are placed in drops at the joints of terminals to improve transmission of light; the devices are compressed by pushing the wedge-shape fixed block to reduce the gap of the folded sheet metal and thus the two fibers are compressed and butted; and the tail optical fiber is jam-packed only in the hole formed in the device.
The sheet metal with the above structure will become deformed both due to expansion and contraction along with temperature changes and due to aging along with time. This will make the distance between the end faces of the two impacted optical fibers increase, resulting in a seriously declining connection indicator.
In the other method, the optical fibers are butted by hitching folded plastic blocks to fix the ends of two optical fibers. Wherein, one of the folded plastic blocks is arranged with a V-groove for butting the optical fibers, and a compressing block that is higher than the outer flank of the housing body is arranged on the backside; liquid substances are placed in drops at the joint of terminals to improve transmission of light; the devices are compressed by pushing the compressing block on the backsides of the folded plastic blocks to reduce the gap of the folded plastic blocks, and thus the two optical fibers are compressed and butted; and the tail optical fiber is jam-packed only in the hole formed in the device.
The plastic block with the above structure has a lower degree of finish than that of the sheet metal and its surface is not smooth. The plastic parts may be scratched by the fiber cutting edge when the fiber is threaded, thus generating plastic scrap, which will pollute the butting fluid. This will also make the distance between the end faces of the two impacted optical fibers increase, resulting in a seriously declining connection indicator.
The two methods above require a special tool during the operation of butting the optical fiber. Two optical fibers stuffed according to a fixed-length and pre-defined specifications, are inserted into the special tool at both sides of the tool at the same time. Then the optical fiber connectors and optical fiber sheath are fixed by the addition of the special tool. The special tool is complicated, large, expensive, and inconvenient to carry.